Photocatalysis is a green technology with important application prospects in environmental fields such as wastewater treatment. Here, we synthesized chrysanthemum‐like BiOBr microspheres (CLB0.45) under introduction of structure guide and soft‐template. Natural biomass chitosan (CS) in the precursor of BiOBr successfully suppressed the growth of both (001) and (102) lattice planes through solvent effect, and promote the expose of (110) lattice planes that dominated the photocatalytic performance. Significantly, the polymer chains regulated the nanosheets of BiOBr to accurately self‐assemble. The obtained CLB0.45 had narrower band gap and more active sites due to surface defects, and the photocatalysts have higher photo‐electron hole pairs separation efficiency. And the degradation performance towards RhB (99.7%, 30 min) of the CLB0.45 was increased, which was 4.6 times higher than that of pure BiOBr. The degradation rate of tetracycline (TC) also exhibited excellent (85.3%). The photodegradation mechanism of CLB0.45 was proposed and verified. In summary, the prepared CLB0.45 through structure guiding and soft‐template have a promising future in the photocatalytic purification of organic pollutants.